The present inventive concept relates to a garbage collection method for a nonvolatile memory device.
In general, embedded systems, such as electronic home appliances, communication devices, and set top boxes, employ nonvolatile memory as a storage medium. Nonvolatile memory has the advantages of both random access memory (RAM), which freely writes and erases data, and read only memory (ROM), which preserves stored data even without power.
Also, commonly used flash memory is a nonvolatile memory device that is able to electrically write and erase data. Flash memory is suitable for portable devices because of its advantages of small size, lower power consumption than magnetic disc memories, and fast access time like hard drives.
When data is newly written to a nonvolatile memory device, a valid data block having existing data written therein is maintained as an invalid data block and a data block is allocated thereto to write data to be newly written. Here, when available space of the nonvolatile memory device is insufficient, “garbage collection” is performed to collect valid data blocks into used segment to generate free segments, thereby increasing the available space. In the course of performing garbage collection, operational overhead may be created, resulting in deteriorated performance of the nonvolatile memory device. Accordingly, research into methods for minimizing unnecessary overhead is actively under way.